1. Field of the Invention
The present invention relates to a control system installed in an automobile, particularly to a method and a system for controlling an automobile comprising a plurality of control units using computers to execute various kinds of controls.
2. Description of the Related Art
As a conventional method for controlling each part of an automobile by use of plural control units, one described in A Japan Patent Application Laid-Open 243426/1991 is known.
In this conventional method, plural computers monitor the presence of troubles in each other and execute cooperative operations by changing control tasks in accordance with the presence of troubles in another computer.
Although the control tasks executed in a computer itself can be changed in accordance with the presence of troubles in other computers by the above-mentioned conventional method, a computer does not execute tasks to be executed in another computer, taking the place of another computer in accordance with load states of another computer.
For example, control tasks are executed by such exclusive processors as an engine control exclusive processor, an automatic transmission (AT) control exclusive processor and so on. Then, while some exclusive processor has no control task to execute, the processor has wasteful time not to be utilized. For instance, an automatic braking system (ABS) exclusive processor must execute control tasks for ABS at the braking time. On the other hand, control tasks for the ABS would be wastefully done at the non-braking time.